Elevator doors are frequently objects of different types of impacts, intentional and unintentional alike. The doors may be accidentally rammed against by trolleys, heavy equipment, such as forklifts, etc. In some locations, elevator doors may be vandalized by kicking and throwing objects at them. As a consequence of various impacts, the door panels may bend, or in the worst case, be completely knocked off the door sill.
Currently, there is no reliable method for monitoring impacts, or damage in door components caused by them. This may present a safety hazard, since in the absence of a warning system, the elevator car continues to operate normally. If the doors are damaged to an extent preventing them from working properly, there is a risk of further damage to the door components, when the door operator tries to operate the doors as usual. Even worse, in case the doors are detached from the sill, the dislocated parts may hit other components during elevator car movement. In the case of elevator car door panels, the loose car door panels may hit shaft components. Loose landing door panels may be hit by the elevator car moving at full speed, potentially causing severe damage to elevator components or passengers. Further, damaged landing doors may contain the danger of people falling into the elevator shaft.
Currently, the main impact detection method relies on the disruption of an elevator safety chain, which stops the elevator movement completely. Also elevator users report malfunctions. The drawbacks of the current systems are that some malfunctions that do not lead to the discontinuation of the safety circuit may remain undetected. The inventors have thus recognized the need for an improved detection method for impacts directed at elevator door panels, in order to further improve the reliability of elevator function and user safety.